Wood chipper



2 Sheets-Sheet l Dec. ZZ, 1953 W. K. VAUGHAN WOOD CHIPPER File-d Deo.l2, 1951 Dec. 22, 1953 w. K. VAUGHAN 2,663,505

woon CHIPPER Filed Dec. l2, 1951 v 2 Sheets-Sheet 2 4 www Patented Dec.22, 1953 TED TENT OFFICE 5 Claims.

This invention relates to wood chippers of the type which are usedindustrially for the purpose of cutting Wood into small pieces or chipsof suit able size preparatory to the manufacture of wood pulp for use inthe production of paper, paper board and the like. The invention relatesparticularly to the mounting of the knives on the chipper disc.

Wood chippers usually comprise a rotatable disc having a series ofknives er blades which eX tend at a suitable cutting angle a shortdistance above the surface of the disc and which are usually spacedsymmetrically around the working face of the disc radially ortangentially of the disc hub. Usually, a plurality of knives or bladesare mounted on the disc and heretofore it was thought importantadvantages were gained bv spacing the knives such that two or more kn swere in engagement with the log at one time. The log to be chippedusually is fed to the disc through an inclined feed spout or chute whichbrings the end of the log against the surface oi the where it is engagedby the knives or blades.

Heretofore, the knives or blades have been mounted with the cutting'edges adjacent to slots which extend through the disc and through whichthe chips are discharged as they are cut from the log. This conventionalarrangement of knife or blade mounting and slots has several inrportantdisadvantages.

The trend over recent years has been to de sign the dise and thearrangement of the knives such that the end of the log is engaged by twoor more knives or blades at one time. This is accomplished by mounting aplurality of knives on the disc and by spacing the knives as closely aspossible. As the disc structur is progressively weakened as the spacingbetween the knife slots is decreased, particularly adjacent to the hub,and, accordingly, the number of knives which can be mounted on the discis restricted. Also, the knives must be spaced a substantial distancefrom the hub of the disc to avoid weakening the disc, and this has thedisadvantage that only relatively large diameter logs can be engagedsimultaneously by two or more knives and small logs are engaged only bya single knife with attendant variations in chip sizesandinereasedproduction of sawdust and bruised chips. A furtherdisadvantage is that it is necessary to provide, at the discharge sideoi each slot a device known as a card breaker to break the oversizechips or cards as they pass through the slots into chips of a desireduniform size suitable for the sub- (Cl. Zal-278) sequent cookingoperation to form wood pulp. Also, the chips as they pass through theslots, lose their momentum and it may be necessary to provide a blowerattachment, such as a vane, on the outside of the chipper disc, to blowthe chips clear of the slots. Chips tend to get caught by this vaneattachment with attendant increase in the production of bruised chipsand fines.

An important object of this invention is to' provide a knife mountingfor a chipper disc which is mounted on the surface of the disc and withwhich the conventional knife slots are eliminated.

A further important object of this invention is to provide a knifemounting for wood chippers in which the knives or blades can be extendedto a point adjacent to the hub of the chipper disc without weakening thechipper disc.

A further important object oi the invention is to provide a knifemounting for wood chippers in which the chips are broken into asubstantially uniform size as they are cut from the log and aredelivered to and discharged from the periphery of the knife mountingassembly.

A further object of the invention is to prom vide a knife mounting forwood chippers which permits the arrangement of the chipper disc and theflywheel and/or the driving pulley as an integral unit to provide acompact and sturdy design.

A still further object of the invention is to provide a chipper disc inwhich the rate at which each knife blade engages the end of the log issuch that the log does not have an opportunity to rebound from the faceof the disc at the end of the engagement of one knife before it isengaged by the next following knife.

An understanding of the manner in which the above and other objects ofthis invention are attained may be had from the following description,reference being made to the accompanying drawing, in which;

Figure l is a side elevation oi a wood chipper incorporating theimprovements or the present invention;

Figure 2 is a front elevation;

Figure 3 is an enlarged detail view; and

Figures 4 and 5 are detail views.

Like reference characters refer to like parts throughout thespecification and drawings.

Referring to the drawings, the numeral iii in dicates a chipper discenclosed, during operation, by a removable cover i l. The disc, usually,is in the form of a heavy casting. The disc is mounted on a shaft 2 andis driven from a motor, not shown, through a driving pulley lia.

edge thereof extending at an angle to the outer surface of said support,means extending rearwardly of each knife blade support towards butstopping short of the cutting edge of the next following knife blade,and a passageway for wood chips defined by said last mentioned means,the opposing surface of the disc and opposing faces of adjacent knifeblade supports, said passageway extending from end to end of said knifeblade supports.

2. In combination with a wood chipper comprising a rotatable disc, aplurality of pairs of clamping members mounted on and secured to asurface of said disc and symmetrically arranged thereon in a generallystraight line extending from a point adjacent to the hub of the disctowards the periphery thereof and extending beyond the surface of thedisc, a knife blade secured between each pair of clamping members with acutting edge extending at an angle to the outer surface of the clampingmember, means extending rearwardly of each knife blade support towardsbut stopping short of the cutting edge of the next following knifeblade, and a passageway for wood chips defined by said last mentionedmeans, the opposing surface of the disc and opposing faces of adjacentknife blade supports, Said passageway extending from end to end of saidknife blade supports.

3. In combination with a. wood chipper comprising a rotatable disc, aplurality of knife supports mounted on and secured to a surface of saiddisc and symmetrically arranged thereon in a generally straight lineextending from a point adjacent to the hub of the disc towards theperiphery thereof and extending beyond the surface of the disc, each ofsaid supporting means comprising a pair of members adapted to be clampedtogether to form a seat for the rearward 6 edge of a knife blade andhaving opposing faces adapted to engage the rearward portion of theknife blade and support it with a cutting edge thereof extending at anangle to the outer surface of the support, log supporting meansextending rearwardly of each knife blade support towards but stoppingshort of the cutting edge of the next following knife blade, and apassageway for wood chips defined by the log supporting means, theopposing surface of the disc and opposing faces of adjacent knife bladesupports, said passageway extending from end to end of said knife bladesupports.

4. A wood chipper according to claim 3 in which the face of the knifeblade supporting member below the leading edge of the knife blade isarcuately curved from the knife blade to the surface of the disc.

5. A Wood chipper according to claim 3 in which the log supporting meansis in the form of a removable plate carried by the knife bladesupporting member and extending rearwardly thereof towards but stoppingshort of the cutting edge of the next following knife blade.

WILLIAM KENT VAUGHAN.

References Cited in the le of this patent UNITED STATES PATENTS NumberName Date 1,955,640 Knowles Apr. 17, 1934 2,247,665 Ottersland July 1,1941 2,312,612 Wetmore Mar. 2, 1943 2,337,407 Ottersland Dec. 21, 1943FOREIGN PATENTS Number Country Date 45,150 Sweden Mar. 12, 1919 509,844Germany Oct. 13, 1930

